1. Technical Field
The present invention relates to a liquid ejecting head and a liquid ejecting apparatus that each include a pressure generating chamber communicating with a nozzle, and a piezoelectric element changing the pressure in the pressure generating chamber and including a piezoelectric layer and electrodes applying a voltage to the piezoelectric layer.
2. Related Art
Some of the piezoelectric elements used in liquid ejecting heads have a structure in which a piezoelectric layer made of a piezoelectric material capable of electromechanical conversion, such as a crystallized dielectric material, is disposed between two electrodes. This type of piezoelectric element can be used as a deflection vibration mode actuator device in a liquid ejecting head. Ink jet recording heads are a typical type of liquid ejecting head. An ink jet recording head includes a vibration plate defining a part of a pressure generating chamber communicating with a nozzle through which ink droplets are ejected. In the ink jet recording head, a piezoelectric element deforms the vibration plate to apply a pressure to the ink in the pressure generating chamber, thereby ejecting ink droplets through the nozzle. In some cases, a plurality of piezoelectric elements are provided for respective pressure generating chambers by dividing a uniform piezoelectric material layer formed over the entire surface of a vibration plate into shapes corresponding to the pressure generating chambers by photolithography.
The piezoelectric element can be made of lead zirconate titanate (PZT), as disclosed in, for example, JP-A-2001-223404.
On the other hand, piezoelectric materials containing lead-free ferroelectrics are desired from the viewpoint of environmental protection. An example of the lead-free piezoelectric material is BiFeO3 having a perovskite structure expressed by ABO3. However, for example, BiFeO3-based piezoelectric materials are less insulating and can cause leakage current. This problem can arise not only in liquid ejecting heads represented by an ink jet recording head, but also in piezoelectric elements such as actuator devices used in other apparatuses.